"I was wrong [about Mr Corbyn]. I am very surprised, an earthquake has happened in British politics and I did not foresee it," he told BBC.

The former business secretary added that he remained unconvinced by Mr Corbyn’s ability to win a majority down the line, but said his “sure-footed campaign has been able to inspire a lot of strong and passionate support but now he has to go beyond that”.

"If he wants the Labour party to win then he's got to build on what he's achieved," he added.

Lord Blunkett, another key figure of the Blair years, praised the Labour leader’s “superb job” in mobilising voters, having previously predicted that the party would be “annihilated” at a general election on his watch.

“All credit to Jeremy Corbyn. The anti-austerity campaign that he led has been extremely effective, backed up – it has to be said – by those who didn’t always agree with him,” he said.

“I just want to say this to Jeremy: you’ve done a really superb job at mobilising, including young people. Could we mobilise in parliament behind you by you being a statesman, not just a campaigning leader but someone who’s prepared to say ‘yes, I will heal the rift, I will reach out, I will have an elected Shadow Cabinet’?”

'I WAS CLEARLY WRONG'

Owen Smith, who challenged Mr Corbyn last year for the top job last year said he was “clearly wrong” in his expectations of what he could achieve.

“It’s a very good night for Labour. We haven’t won, unfortunately, but it’s an excellent performance and Jeremy Corbyn needs to be congratulated for it...

“I was clearly wrong in feeling that Jeremy wouldn’t be able to do this well. And I think he’s proved me wrong and lots of people wrong and I take my hat off [to him]...

“I don’t know what Jeremy’s got but if we could bottle it and drink it we’d all be doing very well.”

Ed Miliband praised Mr Corbyn on Twitter, having called for his resignation following last year's EU referendum.

Congratulations to @jeremycorbyn for his inspired campaign. He showed people a vision of a fairer society and millions voted for change.

Former Shadow Business Secretary Chuka Umunna, who took to the back benches following Mr Corbyn’s 2015 leadership victory, said the leader was among many who deserved credit for the party’s campaign.

“The strong, positive campaign nationally has deprived Theresa May of a mandate to pursue a hard Brexit that we feared and that’s a cause for celebration, I’m very happy about that and Jeremy deserves credit for that too," he told Sky News.

Mr Umunna, who has not been a vocal Corbyn critic, later said on LBC that he would now be prepared to take a Shadow Cabinet job under Mr Corbyn.

"Yes, if I'm asked but I make absolutely no presumptions," he confirmed.